The present invention relates to a transmission arrangement for a motor vehicle, wherein the transmission arrangement comprises a control device, a machine power electronics system, and an electric machine which includes a plurality of windings which are connected to the machine power electronics system via particular phase conductors, and wherein the machine power electronics system is connected to the control device.
Such a transmission arrangement further generally includes a housing, on which the electric machine is located, and in which a fluid sump, which has a fluid accommodated therein, is formed.
The present invention further relates to an electric machine arrangement for such a transmission arrangement and to a method for detecting the machine temperature of such an electric machine.
In transmission arrangements of the type utilized in drive trains of motor vehicles, electric machines can be utilized as an electric motor for providing drive power for the motor vehicle, for example in a hybrid drive train. It is also known to automate transmission arrangements of such drive trains, wherein the actuator system can include electric motors. The electric motors can be utilized, for example, either directly as actuators or as a drive for pumps of a hydraulic arrangement.
As mentioned, such transmission arrangements generally comprise a housing, within which a fluid sump is formed. With respect to the automated actuation of such transmission arrangements, it is important to know the temperature of the fluid accommodated in the fluid sump. The fluid, after all, is generally an oil, the viscosity of which depends comparatively greatly on the temperature. Consequently, depending on the temperature of the fluid, other boundary conditions can result for the control of components of the transmission arrangement, such as, for example, shift clutches or even start or separating clutches. In many cases, such hydraulic arrangements also include electric motor-driven pumps for providing cooling and/or lubricating fluid. The cooling and/or lubricating fluid can be fed, for example, to transmission components or to a wet-running multi-plate clutch.
In order to detect the temperature of the fluid, it is known to situate a temperature sensor in the fluid sump.
Such a temperature sensor is expensive, however. Furthermore, it is difficult to check the proper functioning of this fluid temperature sensor. Document DE 10 2012 016 591 A1 describes a method for determining temperature in a hydraulic arrangement, wherein the temperature of a fluid is determined on the basis of a relationship, which is specific for the hydraulic arrangement, between the speed of the electric motor and the temperature of the fluid at a predetermined pressure of the fluid.